US1710182A - Automatic telephone system - Google Patents

Automatic telephone system Download PDF

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Publication number
US1710182A
US1710182A US14001A US1400125A US1710182A US 1710182 A US1710182 A US 1710182A US 14001 A US14001 A US 14001A US 1400125 A US1400125 A US 1400125A US 1710182 A US1710182 A US 1710182A
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Prior art keywords
office
selectors
selector
trunk
incoming
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Expired - Lifetime
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US14001A
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Martin L Nelson
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Automatic Electric Inc
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Automatic Electric Inc
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Priority to FR613344D priority Critical patent/FR613344A/fr
Application filed by Automatic Electric Inc filed Critical Automatic Electric Inc
Priority to US14001A priority patent/US1710182A/en
Priority claimed from GB916525A external-priority patent/GB254790A/en
Application granted granted Critical
Publication of US1710182A publication Critical patent/US1710182A/en
Anticipated expiration legal-status Critical
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q3/00—Selecting arrangements
    • H04Q3/0016—Arrangements providing connection between exchanges

Definitions

  • My .iiwcntion relates in general to auto matic telepln'ine systems, but more purticularly to such autennitic systems include n number of dill'erent oilices or exchanges,
  • the invention has a number of different zspects, or distinct features, which, however, can. best be pointed. out in the course of av more. detailed description of the system in ciimnection with the acc nnpanying drawings.
  • the drawings may now be described. more in detail, reference being first had. to the lay-out of the lhlidwuy office, Fig. 1.
  • the reference letter A indicates a. subscriber-is station of the usual automatic type. At the Midway e'ilice, with which the substation.
  • the subscribers line terminates in the usual line or trunk selecting switch L.
  • a number of these line switches have common access to a. group of first ofiice selectors, such as the selector FS, which will be referred to hereiiniili'ter for convenience merely as a first selector.
  • the trunk extending from the line switch first selector FS is in two sections, and at the junction of these sections a relay group is provided.
  • This relay group is indicated in the drawing by the reference letters RG and its Function, briefly stated, to enable a director to be associated with the. trunk while a connection is being set up thereover and.
  • trunk lines such as the one shown extending to the il'irst selector F8 are divided into groups, the number of trunk lines in each group depending upon the cnl'izicity oi a liuder switch such as F. For example, if the finder switches each have a capacity oil? twentydive lines, then the trunk lines will be divided into gl'QHPS ot twenty-five each. Each of these groups of trunk lines is served by a.
  • trunk lines in a group in a group.
  • the toregoing arrangement is clearly illustrated in the drawing, in which the director D is indicated as having access to the trunk line extending to the first selector FS by means of the finder switch F unda. branch of the trunk line oxierujling downward from the relay group Rt ⁇ . This branch is clown indicatedby two parallel linen, accessible to two wipers oi? the finder, because of the fact that it includes both incoming and outgoing cir ends to and from the director.
  • the first selectors such as FS, otherwise known as ofiice selectors, are used to select trunk lines to the difi'erent o'lliceso't' the system or local trunk lines, and'in case the total number of groups of trunk lines is within the capacity of a single selector, that is, not more than ten, only a single order of switches will be required. In other words, all the trunking outgoing from the Midway otiice could be means of first selectors only. in a large 111llltl-0lll6 system, however, it will usually be the case that considerably more than ten groups of trunk lines are necessary, from which it follows that second selectors will have to be used in addition to the first selectors.
  • FS otherwise known as ofiice selectors
  • the number of groups of second of course, depend upon the nuniber of groups of trunk lines.
  • the drawing indicates a group oi" second selectors accessible from the second level of the first selectors, one second selector, SS, being shown. These second selectors "give access to ten groups of trunk lines, and it it be assumed that the remaining levels of the first selectors are used for trunk lines also, will be nineteen This can be in groups of trunk lines.
  • tor the Midway office level in either the The local trunk lines may be taken off trorn.
  • the trunk lines are taken otl'f roin the fifth l-vei of the second selectors, one of these trui l: lines being indicated. in the drawing as extending to the thousands selector T.
  • the thousandsselectors have access to ten groups or hundreds selectors, such 7 as the selector H, and the hundreds selectors connectors such as the connector G.
  • the connectors will have access direct to the subscribers lines which are associated with the Midway otlice.
  • the trunks out-going from the lllidway otlice to other main otlices include repeaters. e, if there are more than ten trun rs ina grou 1, secondary line switches may be used in orderto give all the selectorswitches common access to all the trunlrs'. This arrangement is indicated in the drawing, where itwill be seen that'the outgoingtrunks from the sixth level of the first selectors such as 1 S terminate accomplished by thousands selector T.
  • trunk lines incoming to the Midway otlice from the Main otlicc one of which trunk lines is shown as terminating in the incoming selector IS, the banks of which are inultipled with the banks of the
  • the incoming trunks from the sub-exchange Riverside do not terminate in incoming selectors as do the trunk lines troin niain exchanges, but terminate in line switches; This is shown in the drawing where it will be seen that the trunk lines from Riverside to hfllidway come from the bani-cs of secondary line switches such as L in Riverside, and terminate in line switches such as L in Midway.
  • the latter line switches may be inultipled with certain groups of primary line switches, such as t e line switches L and If, associated with substations A and A, respectively.
  • The'l-ay-out ot the Main ol'lice follows the same general plan that has been explained in connection with the Midway ofiice, except for certain changes in the arrangement oi the otfice and incoming selectors. In view of this,the subscribers lines and the direc' tors are not shown, and th hundreds sclec tors and connectors have been omitted also,
  • the firstselector such as FS may have access to certain groups oi direct trunks to other offices, although none are shown in the drawin
  • These selectors inay groups ct second selectors, two such groups being indicated in the drawing, which shows a trunk line extending from the fifth level of the first selector FS and terminating in the second selector SS, and also a trunk line extending from the first level of the selector FS and terminating in the second lcctor SS
  • the thousands selectors for the Main oliice are reached by way of the first level of the latter group of second selectors.
  • the Riverside exchange although it i given an oliice name or designation likeamain. exchange, is not a. main office but what is known as a sub-office and is subsidiary to the Midway office.
  • the capacity of the River? side sub-oilice is one-thousand lines, the particular thousand used being the fifth thousand of the ten diiferent thousands which are part of the Midway office, this fifth thousand being used for the Riverside sub-office instead of being used in the main exchange.
  • One of the branch exchange sub-stations is indicated by the reference letter A and the reference letter L indicates theindividual line switch in which the line of this station terminates at the sub-oilice.
  • Lineswitch L together with a number of other similar line switches, given access to a group of so-called switching selector repeaters, oneof which is indicated by the reference letters SSH.
  • SSH switching selector repeaters
  • SSR switching selector repeaters
  • Associated with each switching selector repeater is a secondary line switch such as the line switch L by means of which access is had to trunk lines extend ing to the main or change.
  • the switching selector repeaters such as SSR have access to hundreds selectors, such as the hundreds selector DH.
  • incoming trunks from the ldidway ofiice terminate in incoming selectors such as IS, the banks of which are multipled with the banks of the drop-back selectors.
  • the first call to be explained is a call from the substation A in the Midway office to another substation, A for .lilSl'lli'CQ, in the same otlice.
  • Thetelephone number of sustation A may be assumed to be MlDway There is nothing); new involved in a local connection of this kind, but it is thought best to take up the simplest case first in order that the entire trunking scheme may be thoroughly understood from the beginning.
  • the line switch L Upon removal of the receivcr at substation A, the line switch L operates in the usual manner to select a trunk line extending to an idle first selector. Assuming that the trunk line extending to the first selector FS the one taken for use, certain relays in.
  • finder F which is associated with an idle director.
  • finder F operates and connects this director with the trunk line, extending, the callim, line through to the director so that the callinc subscriber can set the register switches therein and establishing a control circuit eK- tending ahead over the trunk'liue to the first selector F5.
  • the calling subscriber. now-operates his dial in accordance with the three letters Mil) of the telephone number of the desired station, and then in accordance with the four digits of such number.
  • the letters MID which are equivalent to the digits 515, are registered by oiiice registering; equipmcnt'in the director, while the four digits of the number are reo'istm'ed on digit registers in the director.
  • a sender switch in the director starts to send out the several series of impulses which are neces sary to control the office lectors in order to trunk the call to the desired oliice, which in this case is the local or or imtinh; oilice. It will he necess ry, thereto 1,-to trunk the call to an idle thousands selector in the Mid ay ofiicc.
  • the sender in the director is controlled in accordance with the setting of, the oiiice registering apparatus. Any particular oiiice registration can be'ma-de to cause the transmission of any phone by a series I the called station.
  • the im- 7 readily changed whenever it is necessary or desirable to do so.
  • the director now transmits the four digits of n second scicc the number as they were registered, operat-' ing the selected thousandsselector, a hundreds selectors suchas H, and a connector such as C, to complete the connection to the desired station.
  • the finder switch F isreleased in order to free the director and the t *0 sections of the first selector trunk line are united at the-relay ,roup RG, thus finally completing the connection between the calling and
  • the next case which will be considered is the case of a call from one office to second office which is connected to the first office ver direct trunks.
  • a typical case of this hind is a call from Midway office to Main oflice.
  • the calling line- is extended to'an idle first selector such as FS,
  • the calling subscriber now operates li-a n "p ,11 1 un 1% ms t 1a 111 LCLOl ounce an n the cesnec e c number and the severailctters and digits called are registered in the director.
  • the office code into which the office portion of thenumber must be translated is ($21, as may be readily ascertained by tracing the trun route from the bank of the first selector'FS in he Mid sends selector T.
  • the director proceeds to transmit series of impulses in accordance with the ofiice'code 621, the first digit of which raises the first selector FS to the siXth level.
  • this line switch is operated to select an idle outgoing trunk to the Main office. ⁇ Ve may assume that the trunk line shown is selected, whereby it follows that the secondary line switch will stop on such trunk and extend the connection through the repeater R to the incoming selector IS in the Main office.
  • the next series of impulses transmitted bythe sender operates the incoming selector TS to the second level, and such selector then automatically selects an idle second selector. Assuming that the second selector SS is the one taken for use, this selector is then raised to its first level, responsive to the third series of impulses in the office code, and then operates to select a trunk line leading to at thousands select-or. ⁇ Ve may assume that the thousands selector T is the one selected. After having transmitted the office code, the director then proceeds to transmit the four registered digits, which are effective to operate the thousands selector T, together with a hundreds selector and a connector (not shown) in order to complete the connection to the desired called station.
  • the first call of this general type which will be considered is a call which involves tandem trunking ,over a single route and through one tandem office.
  • a call from the Midway office to the North office is a call ofthis kind, and the process of setting up such call will ,now be briefly explained.
  • the subscriber at station A desires to call telephone number NORth 123i, and that the same apparatus in the Midway office is used as in the preceding cases, when the subscriber dials the desired number the office portion of the number and the several digits are registered in the usual way.
  • the directors in the Midway office are so cross connected that the office desi nation NOR (602) is not translated, the ofhce code in this case being the same as the numerical equivalent of the letters in the office designation. This, of course, is an unusual case but one which might well occur.
  • the office code 602 is transmitted by the director, selectors FS in the Midway office, IS in the Main office, andlS in the North office are As soon as the office por-' ill) til)
  • connection is extended to an idlethousands selector in the North oflice such as the thousands selector T.
  • a secondary line switchL is shown as being inserted between the incoming selector 1S and the repeater R in the Main office. This arrangement is similar to the arrangement shown in connection with the first selector FS and needs no special consideration.
  • the connection having been extended as far as the thousands selector T in the North ollice, it will be readily understood that, as in the preceding cases, the remainder of "the connection is established by operating such thousands selector, a hundreds selector, and a connector in accordrmce with the registered numerical digits of the called teleplmne number.
  • he trunking commotion may be tracedfrom he sixth level of the first selector ES in he lrlidway other, by way of the eighth of the incoming selector IS in the otlice, tenth level of the incoming sele tor Thi in the South otlice, and fifth level he second
  • a typical call of this class is one from a station in the lrlidway oilire to a station in the East office, such call being trunlredthrough the Main and North tandem otlices. l nview of what has been said before, the operations pertor-med in trunking the call to the desired o'tlire vill not need any explanation except to point out the trunk route which is taken,
  • the third level On this level are ter- I that in the Midway oflice the ollice code for the East ollice is 6033, that is, when any subscriber in Midway oilice calls a number in the East office the otlice designation ELS (623) is translated by the director in use into the otlice code 6 33.
  • tandem trunking over alternate routes will next he considered. Calls from Midway to East will be used as an example. As described in the last case, these calls may be routed to the, East olh'ce via the Main and North tandem omens. Another route, however, is equally available, this alternative route bemg by way of the Main. and South tandem otlices.
  • the olliee code 'lorlhe East ottlce at the 'h I idway otlice may Well be (5823 instead of (S033.
  • each group of trunks handle calls to as many different exchanges as possible because the pealtload to the different exchanges usually occurs at different times, and if traffic to a number of different exchanges is handled on a single group of trunks the load on the entire group will be better distributed.
  • the required div sion of traliic is accent rectors in the Midway office so that they will translate the East oilicedesigmiion 6033 and by cross-coir way officeso that they will translate this office designation into the oilice code 6823. If it is desired to divide the trathc equally, one-half the directors in Midway will be cross-connected one way; and one-half the other way. Any desired portion of the traflic can, of course. be diverted to either the North or South otlices by suitable changes in the number of directors that are crossconneetedone way or the other, and since quite a large number of directors are involved as fine a. division as is necessary or desirable can easily be obtained.
  • the tratlic may also be divided in accordance with the location of the originating station, since it this station is at a some what remote point, the 01 ll should obviously be routedto its destination by way of the best and shortest route. Considering calls originating the hflidway ollice and at the Riverside sub-ollice for example. These calls are all handled by the directors in the lllidway ollice, but those calls'which originate at Riverside obviously should be given the best route because of the added trunk cable involved.
  • trunks to heavy tandem ollices are taken first selector banks rather than from a. level in the second, srle banks wherever possible, as ,”hown in the case of the trunks extending .l roiu the Midway otlicc to the lrlain tandem ollice. which come from the sixth. level oi. the first 'se lectors.
  • the second selectors SS have ac s to the local thousands selectors in the slain oflicc' such as T, so that the incoming selectors IS" and IS", whose banks are multipled with the banks of the second selectors SS", will also have access to such thousands selectors.
  • the incoming selectors IS however,'access to such thousands selectors 'would be barred were it not for spccialprovisions, and certain situations might arise in which the incoming selectors IS would have to be multipled with the first selectors BS in order to give them access to the thousands selectors in question.
  • how- 'it is assumed that there is a vacant selectors SS which is not in use toroutgoin ii-units.
  • the corresponding level will be vacant in the banks or incoming sclectccrsIS and can be used for trunking from such incoming selectors to the group of second selectors SS
  • the group of second. selectors such as SS is made accessible from the first level of the firstselectors such as FS and also from the second level ot the group of incoming selectors which include IS and the neces sary access had while still obtaining the maximum economy in otlice dig'ts.
  • each group oi incoming selectors in each oflice is multipled with the particular order of switches which will give access to all required points, and that no more orders of switches are included than is absolutely necessary.
  • the trunks from the North oitice to the South office a still greater economy is possible than in the case previously discussed.
  • trunks from the South ofiice to the East ofiice which trunks are accessible from the second level of the first selectors such as FS", and also from the third level of the second selectors such as SS".
  • the reason for multipling these trunks to the banks of the second selectors SS is to enable the incoming selectors such as IS to be multipled with-this group of second selectors rather than with the first selectors such as.
  • This latterline switch now operates also and selects a trunk leading to an idle first selector in lvlidway. Assuming that the first selector FS is taken tor use a circuit is completed at the. relay group tG by means of which an idle director such as I) is connected to the trunk line by means of a finder suchas F. ()n dialling the first digit of the number the switching selector repeater SSR is raised to the fifth level and at the same time impulses are repeated over the trunk line to the Midway otticc and the digit is registerediu the director I).
  • the switching selector repeater SSR Since the first digit dialled, the digit 5, has deli nitely determined that the "call is not intended for the Riverside sulrofiicc, the switching selector repeater SSR remains standing opposite the fifth level and does not further respond to the operation of the calling device at the calling station but merely acts as a repeater; The remaining digits of the number, therefore, including the two digits 1 and'6 ol, the ollice designati on and the numerical digits 1, 2, 1, and at, are repeated over the trunk line to the director in use and are registered therein precisely the same as tl'rough the call was originatetfl by a subscriber in the Midway office. It will be understood, therefore, that the director will trunk the call to a thousands selector such as T by translating the office designation into the necessary code, after which it will operate such thousands selector, a hundreds selector such as H, and
  • a connector such as C, to complete the connection to the desired called station.
  • a first office, :1 second office fwo inhervening ftondein offices, u group of direclors in said first oflicc com mon lo u plurnlile, of lines lermiual'ing in such office, said direclors comprising menus for l'ruuking calls ilrl'un said lines to the required offices, circuit roimec'tions in ccrloin of said directors provii'ling for trunking; calls from said lines lo said second office viii, one e paid lenders offices, and different circuil (fiuli'lQCilOilS in the ren'mining direc mean providing for lrunliing cells from said lines lo sir-id secondoflicc Via the other land 1m office.
  • second office fwo intervening tandem. oflices, directors in the firsl' office for controlling the extension of calls from the first office to (he second office through said f zmdem offices, and means in said directors for lvrunking cells of. u oer-loin class l'o said secinid oflicc 'Vllb lhc faundem office while calls of unolher cluss ore :unlicd to said second office viii said second tandem office.
  • first office selectors In :1 lnndem office, first office selectors, second office selectors accessible to said first office selector-re incoming: seleclors having their banks u'uilfzipled with the banks of said second office selecl'ors, and a group of trunk lines multipled in the banks of all said selc :fors
  • switching selector repeaters accessible :to the subscribers lines, digit absorbing selectors directly accessible to said selector repeaters, and connectors aecessible to said selectors.
  • switching selector repeaters accessible to the subscribers lines, digit absorbing selectors directly accessible to said selector repeaters, connectors accessible to said selectors, and incoming lectors having their banks multipled it'll the banks or said selectors.
  • switching selector repeaters in said subollice arranged to switch responsive to the last letter in a local tel phone number, selectors in said sub-o'ltice adapted :to absorb one otthe digits in such telephone number and operate responsive to another, and connectors in the sub-oilice responsive to the lasttwo digits.
  • trunks extending from the banks of said otlice selectors to in: coming; selectors in said combination office, switchingselector repeaters in said combination olliee for handling, local calls and for repeating trunked calls to main oiiice, and directors in said main otlice for han7 tiling calls originating in the manic ice and the calls which are trun'lred to such 'otlice from the combination oilice.
  • a first ofiice a second OiliCG, directors in said first office for trunking; calls from said first oiiice to said second oflice in accordance with otlice codes, there being two such codes which may be used, one code comprising more dig L than the other, and circuit conneetions in said directors such that part of the said directors will use one code while other di rectors will use the other code.
  • a multi-ofiice telephone system including telephone otlices each designated by the same number of characters as any oneo't' the others, one of said oliices being a .tandem oitice, two outgoingtrunk line groups outgoing from said tandem ()lllf e to two other o said otliccs, respectively, two trunk line groups.
  • two outgoingtrunk line groups outgoing from said tandem ()lllf e to two other o said otliccs, respectively, two trunk line groups.
  • a third incoming trunk line group said automatic switching mechanism bein o ierable to extend connections from said 'ilill'Cl incoming trunk line group to telephone lines terminating in said :tandem oilicc. but not to either of said outgoing trunk line groups.
  • a 'mult-oliice telephone. system including a plurality of main oliices, a subol'lice subsidiary to one oi said main offices, the lines of said sub-otlice having :assigned thereto numbers displacing a block of numbers of said main ollice, each of said olhces having assigned thereto :a designated separate and distinct :trom the designation of every other one of said oliices, and switch- 111g apparatus controlled an accordance with the ollice designation of the sub-oflice when call to the sub-ofii 'e is being made and controlled in accordance with the office designation of the associated 'main office when a call to the main ofiice is being made tor extending; the connection to :the main otlice in both cases.
  • a suboiiice subsidiary 'to one of said main ofii'ces.
  • the lines of said sub-o'ltice having assigned thereto numbers displacing a block ofinumbers of said main ofiice, each of said offices having assigned thereto a designation separate and distinct from the designation of every other one of said otlices, inter-oilicetrunking switches controlled in accordance with the office designations of the respective ofiices, numerical switches controlled in accordance "with the remaining portions of the subscribers numbers, and means for operating the inter-ollice-trunking switches in the same way whether a call. is for said sub-oliice or for :its associated main office for trunking the call to one of the numerical switches in the main ofiice.
  • a calling ofiice, three other ofiices, intcw-o'llice trunking arrangements surl'rthat a call to any one of said other oliices from said calling otlizte may he completed by Way or" the other two of said other o'flices, and means including translating apparatus in the calling oliice for bringing about said routing.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Exchange Systems With Centralized Control (AREA)
  • Interface Circuits In Exchanges (AREA)
US14001A 1925-03-09 1925-03-09 Automatic telephone system Expired - Lifetime US1710182A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
FR613344D FR613344A (en, 2012) 1925-03-09
US14001A US1710182A (en) 1925-03-09 1925-03-09 Automatic telephone system

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US14001A US1710182A (en) 1925-03-09 1925-03-09 Automatic telephone system
GB916525A GB254790A (en) 1925-04-06 1925-04-06 Improvements in or relating to telephone systems

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2665375A (en) * 1948-09-09 1954-01-05 Gen Electric Co Ltd Radio telephone system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2665375A (en) * 1948-09-09 1954-01-05 Gen Electric Co Ltd Radio telephone system

Also Published As

Publication number Publication date
FR613344A (en, 2012) 1926-11-15

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